Isomorph invariance of dynamics of sheared glassy systems
Isomorph invariance of dynamics of sheared glassy systems
复制标题
剪切玻璃体系动力学的同构不变性
DOI：
10.1103/physreve.100.053005
复制
发表时间：
2019
影响因子：
2.4
通讯作者：
Bailey, Nicholas P.
中科院分区：
文献类型：
--
作者：
Jiang, Yonglun;Weeks, Eric R.;Bailey, Nicholas P.
我们研究了 Kob-Andersen 二元 Lennard-Jones 系统玻璃相中的隐藏尺度不变性。冷却到玻璃化转变以下后，我们从系综中势能和维里的涨落中生成所谓的同构：一组密度、温度对，当以适当的简化单位表示时，其结构和动力学是相同的。为了获取动力学特征，我们使用 SLLOD 算法结合 Lees-Edwards 边界条件来剪切系统，并研究应力波动和横向于剪切方向的粒子位移的统计数据。我们发现统计数据的良好崩溃，表明同构理论在这种情况下运作良好。对应力波动的分析，特别是给定应变间隔内应力变化的分布，使我们能够以负侧指数尾部的形式识别雪崩行为的清晰特征。这个特征也是同构不变的。简要讨论了同构对可塑性理论的影响。
We study hidden scale invariance in the glassy phase of the Kob-Andersen binary Lennard-Jones system. After cooling below the glass transition, we generate a so-called isomorph from the fluctuations of potential energy and virial in theensemble: a set of density, temperature pairs for which structure and dynamics are identical when expressed in appropriate reduced units. To access dynamical features, we shear the system using the SLLOD algorithm coupled with Lees-Edwards boundary conditions and study the statistics of stress fluctuations and the particle displacements transverse to the shearing direction. We find good collapse of the statistical data, showing that isomorph theory works well in this regime. The analysis of stress fluctuations, in particular the distribution of stress changes over a given strain interval, allows us to identify a clear signature of avalanche behavior in the form of an exponential tail on the negative side. This feature is also isomorph invariant. The implications of isomorphs for theories of plasticity are discussed briefly.